Snap-action switches



y 1961 c. A. BALL, JR., ETAL 2,993,101

SNAP-ACTION SWITCHES Filed Aug. 3, 1959 25 19 11 31 BY d 30 THE/R. Azrazezv .s'.

Unite Our invention relates to new and useful improvements in snap-action switches of the type in which quick and positive snap action of the switch blade is obtained by movement of the switch actuator.

An important object of our invention is the provision in a switch of this character of a switch blade having a snap-action movement which will cause the contacts to have a walking effect so as to reduce the possibility of the contacts becoming welded together.

Another object of our invention is the provision in a switch of this character of an arrangement of parts which permits a movable switch blade to achieve snap-action movement between contacts without being deformed through an S shape configuration. The switch blade during its snap-action movement is permitted to attain its maximum longitudinal length against the forces of a compression member and thereafter be bowed in a determined direction.

Yet another object of our invention is in the provision of a switch of this character of an arrangement of parts whereby the contacts are positionable at any point along the longitudinal length of a movable switch blade.

Still another object of our invention is the provision of an actuator for a snap-action switch which assures proper snap-action movement of a switch blade to an actuated position and a like snap return movement of such blade to its normal position.

An ancillary object of our invention is to provide a snap-action switch which is simple in construction, economical in manufacture, and highly eflicient in use.

Other objects will appear hereinafter.

The invention consists in the novel combination and arrangement of parts to be hereinafter described and claimed.

The invention will be best understood by reference to the accompanying drawings showing the preferred form of construction, and in which:

FIG. 1 is a side elevational view of a snap-action switch constructed in accordance with the teachings of our invention and showing in dotted lines the movement of the switch blade;

FIG. 2 is an elevational view similar to FIG. 1 and showing the switch blade in actuated position;

FIG. 3 is a top plan view of our invention;

FIG. 4 is a perspective view of the parts of our invention in exploded relation; and

FIG. 5 is a side elevational view of a modified form of our invention;

FIG. 6 is a diagrammatic view showing in an exaggerated degree the arcuate path of the actuator and switch blade of our invention.

In our improved switch we provide a mounting plate 10 formed of any suitable non-conductive material. A switch blade actuator 11 is fixedly attached by a rivet 12 adjacent one end of the mounting plate 10. This actuator 11 provides a terminal end 13 adapted to be projected through an opening 14 formed in the mounting plate 10.

The mounting plate 10 is provided with a notch 15 formed in one side thereof. Positioned in this notch 15 is a terminal arm 16. This terminal arm 16 is connected to the plate 10 by a rivet 16a.

The arm 16 has a vertically disposed portion 17 extending in a parallel direction to the longitudinal length of the plate 10 as seen in FIGS. 1, 2 and 4. This portion States atent O ice 17 of the arm 16 terminates into a horizontally extending contact carrying arm 18. This arm 18 extends over the plate 10 in a spaced relation as seen in FIGS. 1, 2 and 4. The arm 18 provides an electrical contact 19.

A second electrical contact 20 is provided by a terminal plate 21 connected by a rivet 22 to the plate 10. The contact 20 is so positioned as to be in vertical alignment with the contact 19 carried by the arm 18. The actuator 11 provides a substantially U-shaped section which comprises two spaced apart legs 23 and 24. These legs are connected together by a bight portion 25.

The desired operation of our switch requires that the bight portion 25 be of a rigid nature. In order to assure rigidity of the bight portion 25, such portion is provided along its opposite longitudinal edges with outwardly flaring wings 26 and 27.

Referring to FIGS. 1, 2 and 4, it is noted that leg 2'4 is of a length greater than that of leg 23. By such construction, the leg 24 is adapted to extend through an opening 28 formed in the plate 10. The leg 24 is provided with a reduced portion 29 (FIG. 4) which is of a width equal to the width of the opening 28. Such reduced portion 29 provides stop shoulders 30 which are disposed beneath the plate 10 to either side of the opening 28 and which function to prevent vertical movement of the leg 24 to an extent that it would become withdrawn from such opening.

By reason of the above described construction, the following structural facts are apparent:

As the arm 23 has one end fixedly attached to the plate 10 (by the rivet 12) and the opposite end thereof integrally connected to the rigid bight portion 25, it possesses a degree of resiliency different from that of the leg 24, this by reason of the fact that the leg 24 has one end freely associated with respect to the plate 10, while its opposite end is integrally connected to the opposite end of the bight portion 25.

The required difference in the degree of resiliency between the leg 23 and the leg 24 of the actuator 11 will be hereinafter made apparent.

A switch blade 31 having a longitudinal length greater than the distance between the legs 23 and 24, is shown in FIGS. 1, 2 and 4. To position such switch blade 31, between the legs 23 and 24, it is placed in a bowed condition as seen in FIG. 1, the lateral resiliency of the legs 23 and 24 being sufficient to maintain the switch blade 31 in such bowed condition.

Each end of the switch blade 31 is provided with horizontally extending fingers 32' and 33. The fingers 32 at the heel of the switch blade 31 are adapted to project into spaced notches 34 formed in opposite vertical edges of the leg 23. The leg 24 is formed to provide a V- shaped seat 35 which has its opposite vertical edges terminating into spaced notches 36 into which project the fingers 33 of the toe end of the switch blade 31.

By the employment of the V-shaped seat 35, the toe end of the switch blade 31 has full facial contact with the leg 24 between the fingers 33.

The switch blade 31 has provided on its opposite faces, contacts 37 which are adapted to have alternate engagement with contacts 19 and 20 of the terminals 16 and 21.

Due to the bowed condition of the switch blade 31 when mounted between the legs 23 and 24, one of the contacts 37 carried thereby will be in contact with one of the contacts 19 and 20. This is clearly illustrated in FIG. 1, where it is seen that the lower contact 37 of the switch blade 31 is in engagement with the contact 20 of the terminal 21.

When pressure is applied to the bight portion 25 of the actuator 11, the leg 23 will be caused to resiliently bend in a clockwise direction as seen in FIGS. 1 and 2. One end of the bight portion 25 will commence to move in a downward direction toward the mounting plate 10. Such downward movement of the one end of the bight portion 25 of the actuator 11 will cause the leg 24 to move downwardly through the opening 28 formed in the mounting plate 10., This movement of the leg 24 is imparted to the toe end of the switch blade 31 which is in facial abutment with the leg 24 by reason of the V- shaped notch 35. The toe end of the switch blade 31 from its normal point of engagement A (FIG. 6) will be caused to move downwardly and laterally with respect to the longitudinal length of the switch blade 31 through a substantially vertical arcuate path against the resiliency of leg 24 to a position B (FIG. 6) where it will have attained its full longitudinal length. At the position B, the switch blade 31 will no longer be in a bowed condition.

The degree of longitudinal stress against leg 24 created by the switch blade 31 as it moves to attain its full longitudinal length is sufiicient to overcome the resiliency of the leg 24 and it, too, is caused to move in a substantially parallel plane with respect to the longitudinal axis of the switch blade 31 and simultaneously through a substantially vertical plane with respect to the mounting plate 10; such movement prescribes a substantially vertical arcuate path.

When the actuator 11 is moved in a downward direction to a degree whereby the V-shaped seat 35 of the leg passes beneath the horizontal plane of the switch blade 31, the longitudinal stress of the switch blade 31 against the resiliency of the leg 24 is reduced to a degree whereby the resiliency of the leg 24 will cause the switch blade 31 to bow in an opposite direction. Such bowing action of the switch blade 31 is facilitated by the resiliency of the leg 24, which resilient pressure is sufiicient to increase this reversing bowing action as the leg 24 moves in a direction to the left as viewed in FIG. 2. In such position, the snap-action of the switch blade 31 is completed and the parts are in the position shown in FIG.

When the pressure is removed from the actuator 11, the resiliency of the leg 23 will cause a reverse action and the switch blade 31 will return to its normal position as shown in FIG. 1. In such position, the return movement of the actuator 11 is arrested by reason of the stop shoulders 30 engaging the plate 10 adjacent the opening 28.

The make and break action imparted to the contacts 19, 20 and 37 as a result of the construction of the switch hereinbefore described, is unique, in that the contact 37 of the switch blade 31 has a walking, breaking action with respect to either of the contacts 19 and 20. This is apparent by reference to FIG; 1. There it is shown that the contact 37 has a heel portion engaging the contact 20. As the switch blade 31 is caused to extend itself to its fully longitudinal length, the full face of the contact 37 is forced down upon the contact 20. When such contacts separate, they break at the toe of the contact 37 which is the last part of the contact 37 to engage the contact 20 as the switch blade 31 commences its reverse bowing action. This is known in the art as a walking contact action and is highly desirable.

Referring to FIG. 5, there is illustrated a modified form of the invention wherein the actuator 11 has a longitudinally extending heel portion 38 which is fixedly attached to a mounting block 39 Which, in turn, is secured as at 40 to the mounting plate 10. The remaining construction and operation of the switch is as hereinbefore described. The corresponding structural parts of the modified form of the switch are indicated by identical primed numbers. The same objects are accomplished in the same manner by such modified form as are accomplished by the preferred form.

While we have illustrated and described the preferred form of construction for carrying our invention into effect, this is capable of variation and modification without departing from the spirit of the invention. We, therefore, do not wish to be limited to the precise details of construction set forth, but desire to avail ourselves of such variations and modifications as come within the scope of the appended claim.

Having thus described our invention, what we claim as new and desire to protect by Letters Patent is:

A snap-action switch comprising a non-conductive mounting plate, spaced apart vertically aligned stationary contacts, a movable contact adapted to alternately engage said stationary contacts and separate therefrom by a walking action, and means for supporting said movable contact for said action, said means comprising an actuator substantially U-shaped in form to provide opposite parallel leg portions and a substantially rigid medial portion, a plate carrying the stationary contacts and to which one of the legs is connected, said plate having an opening through which the other leg movably projects, the first leg having a pair of spaced notches and the other leg having a transversely extending seat, a blade carrying the movable contacts and having fingers extending into said notches, the opposite end of said blade engaging in said seat, said blade being of a length greater than the distance between said legs whereby said blade when mounted between said legs will be bowed, said'other leg being resilient to flex laterally under action of said blade and cooperating with said one leg to effect snap-action movement of said blade from opposite sides of its long axis.

References Cited in the file of this patent UNITED STATES PATENTS 2,467,939 Andrews Apr. 19, 1949 2,673,269 Hobbs Mar. 23, 1954 2,743,332 Torres Apr. 24, -6

FOREIGN PATENTS 869,551 France Nov. 7, 1941 

